The present invention relates to a developing apparatus for a copier, printer or like recording machine and, more particularly, to an improvement in a dry process developing apparatus which uses a dry developer for developing a latent image.
Various developing apparatuses have been proposed and put to practical use such as those of a magnet brush type, a cascade type, a fur brush type and a spray type. A magnet brush type developing apparatus, for example, usually includes a casing which is filled with a developer such as a toner and a developing sleeve which is rotatably disposed at the bottom of the casing. A plurality of magnets are accommodated in the developing sleeve so that the toner may be magnetically deposited on the surface of the sleeve and carried thereby toward a photoconductive element by the rotation of the sleeve. The toner is transferred from the developing sleeve to the photoconductive element to develop an electrostatic latent image on the photoconductive element.
In such a developing operation, the toner is transported at a rate which is three to seven times the feed rate of the photoconductive element so as to contact or impinge on the photoconductive element. The toner, therefore, is allowed to scatter in various directions inside a machine upon contact with the photoconductive element. The scattering toner tends to become deposited on chargers, an optical system and other various portions inside the machine, causing irregular charging and/or exposure. Such would degrade a reproduced image bringing about irregularity in image density, background density, etc.
Furthermore, streams of air are apt to entrain the toner as far as an electric power source section and mechanical sections such as drive linkages to invite electrical and mechanical malfunctions or troubles.